The invention relates on the one hand to a vehicle seat with a seat part and with a seat back part for supporting a driver of the vehicle in his sitting position on the vehicle seat.
On the other hand the invention relates to a commercial vehicle, in particular an agricultural commercial vehicle, with a vehicle seat for a vehicle driver.
Generic vehicle seats in particular for commercial vehicles and especially for agricultural commercial vehicles are well known in many forms from the prior art.
In particular, while working with these agricultural commercial vehicles and working equipment attached thereto drivers of agricultural commercial vehicles often adopt over a relatively long period of time a seated working posture which is oriented sideways or backwards, in contrast to the normal posture facing forwards in the driving direction, in order for example to be able to reach better and to operate operating elements disposed laterally at the back of the vehicle cab, or also in order to have a good view for a relatively long period of time of a working device attached behind the agricultural commercial vehicle.
A seat with a seat back is known for example from the publication DE 30 46 049 A1, wherein the seat back or at least a seat back extension which forms an upper part of the seat back is rotatable about a vertical axis so that a driver can better reach operating devices disposed to the rear. Due to the rotatable seat back extension these operating devices can in fact be reached better by the driver. However, when the driver is in a working posture oriented backwards, for example when observing working equipment during use in the fields, he cannot be additionally supported since with such off-centre loading the seat back extension would turn back again into its original position.
In more modern vehicles a vehicle driver can currently swivel the entire vehicle seat, that is to say substantially the entire rigid seat construction together with the seat part and the seat back part, with the aid of a rotary adapter about a defined vertical axis of rotation. In this case the seat part remains stationary in relation to the seat back part. On the one hand this results in the driver of the vehicle having to turn out of a comfortable upholstered seat contour of the vehicle seat in order in particular to be able to actuate the pedals of the agricultural commercial vehicle safely. This can lead to pressure sores and thus to discomfort especially in the buttocks and thigh area of the driver of the vehicle.
Any accessories on the vehicle seat, for example a multifunction armrest, likewise rotate in relation thereto. Operating levers which are disposed further back and to the side still cannot always be actuated comfortably.
The upholstered backrest contour is currently shaped in such a way that the driver of the vehicle has the maximum possible support when in the forward facing seated working posture without losing the necessary degrees of freedom required for his movements when driving. In order not to impede freedom of movement in the shoulder and arm region, the backrest cushion of the seat back part should not be contoured too much in the upper region. However, in order to ensure good support and thus a sufficiently good relief of the strain on the driver, a support surface should always be as large as possible. At present, for the reasons mentioned above, such as the necessary degrees of freedom for good movement, this can only be achieved to some extent since the driver alternates between two extremely different driving positions.
A further disadvantage is that the swivel range of the rotary adapter is limited by the fact that in spite of the possibility of watching the working equipment behind the commercial vehicle the vehicle must also be safely controlled by means of the pedals and the steering wheel. In order to meet these requirements the driver of the vehicle must adopt an enforced posture which inevitably leads to twisting of the entire body. Scientific studies show that such a twisted enforced posture in particular with vibrational stresses can lead to damage to the body structures, especially when the body is not sufficiently well supported. It is also established that the strain on the spinal column can be significantly reduced by good support by means of the seat back part.